An image processing system that performs the functions of forming an image on a sheet and decoloring by heating an image formed by decolorable color material is generally known.
The image processing system heats and pressurizes the image of the decolorable color material and non-decolorable color material transferred on the sheet to fix the image on the sheet prior to discharging the sheet. An image processing system heats the sheet on which the image of the decolorable color material is formed, to a decoloring temperature higher than the fixing temperature to decolor the image prior to discharging the sheet.
The sheets that are discharged include a sheet on which an image is formed using the image forming function, and a sheet on which nothing is printed after decoloring is performed using the decoloring function. If such sheets are discharged on the same tray, the sheet on which the image is formed and the sheet on which the image is decolored are mixed. In such cases, it is necessary to sort the sheets in the discharge tray manually.